Herman Miller Aeron Mesh Office Desk Chair Medium Size B (Medium) fully adjustable lumbar. Fully Loaded With Features. This Aeron was Kept in a storage warehouse but never used. It has Headrest, adjustable lumbar, height, forward tilt, rear tilt, tension control, and fully adjustable armrests. The chair itself is in flawless condition with no damage to the mesh at all. All adjustments work perfectly. Aeron Chair Medium (B) Dimensions without headrest. Seat Height 16-20.5.